Plug valve



1937; 5. J. NORDSTRQM 2,102,211

PLUG VALVE Filed Dec. 19, 1935 l E ias;

key. 28

INVENTOR. Jven J Nora/dram 1 Patented Dec- 1 19327 PATENT OFFICE PLUGVALVE Sven J.;Nordstrom, Piedmont, Calif; assignorto Mei-co NordstromValve Company, Pittsburgh, Pa., a corporation of Delaware N ApplicationDecember 19, 1935, Serial No. 55,238

lz Claims. (o1. 251-}-112 This invention relates to plugvalves. particu:larly of the lubricant jacked type.

It is one object of this invention to provide means for uniformlydistributing a resilient seating thrust to anend of the plug. 7 1

1 A furtherobject is the provision of meansflfor uniformly distributingthe reaction thrust of a resilient cover employed for holding the plugin itsseat. 1

Still anotherobjectis the provision of improved means for lubricatingthe thrust receiving portion of the plug. 1 1

Another object is the provision of improved means for substantiallycompletely sealing the 16 valve passageway in full open and closedpositions by lubricant under pressure. 1 1

According to the present invention, I provide a :fluid chamber betweenaresilient cover and the end of the plug, which is separate from the blubricant system employed in lubricating and jacking the plug, and byintroducing suitable fluid under pressure into this chamber theresilient cover is deflected, theresilient thrust of the cover due toits'defiection being transmitted by plastic material maybe employed forthis purpose, and I prefer to employ a plastic lubricant. The plugenclis lubricated by a spiral lubricant groove which preferably obtains itssupply of lubricant from the plug lubricating grooves.

An improved system of lubricating grooves provides ;a substantiallycomplete lubricant seal around thevalve passageway inwfull open and fullclosed positions of the valveplug, the grooves exposed to line fluidbeing disconnected from the source of lubricant'pressure in intermediatepositions of the plug. This arrangement enables the plug to be jacked bylubricant pressure in all positions. 1 1 The invention will be describedin greater detail in connection with the accompanying drawing, whereinvI p Figurel ls'a verticalsection through a valve showing a preferred:modification of the inven- 1 tion;

Figure 2 is an elevation of the large end of the plug; ,1 11 1 Figure 3is a vertical section through a further modification'of the invention;and 50 Figure 4is a plan view of the plug. 1

Referring to the drawing, there is shown a valve body or casing I,havingga passageway 2 therethrough for flow of fluid and a tapered valveseat 3 transverse to the passageway. ,A

port 5 extending transversely therethrough adapted to register with thepassageway 2 in; open position of thevalve. A threaded operating stem 6extends through the casing at the smaller end of the plug and has atongue I forming an 6 1 operative connection with a depression in thesmaller end of the plug. The outer endof the stem 6 is squared asindicated at Bto receive an operating wrench and a suitable stop collar9 thereon limits rotation of the plug to 90. A 10 lubricant chamber H isformed adjacent the smaller end of the plug, and a threaded boreorreservoir H in the plug stem communicates there-, with. Lubricant isforced from the reservoir [2 by a threaded screw I3 therein into thechamber l5 II for jacking the plugand supplying lubricant to thethreaded stem and valveoperating surfaces, a' secondary packing seal Itbeing provided about the stem to prevent leakage. 1 1

The lubricating system for the valve operating surfaces comprises a'pair of circumferentially disposed grooves l1 and 18 in the casing seateach having a pair oflongitudinal extensions l8 and 20 respectively,connected therewith. A diametrically opposite pair of longitudinalgrooves 22 extend from the smaller end of the plug to thecircumferential grooves l1 and I8 and are adapted to conduct lubricantthereto from the chamber. 'Adiametrically opposite pair or shorterlongitudinal grooves 23 are disposed on the opposite side of port 5 andconnect with the groove extensions '20 and is but, terminate atthe,smaller and of the plug short of the lubricant chamber l l. 1' g Thelarger end of the seat 3 is closed by a metal cover 25 bearing on ashoulder 26 of the casing and a diaphragm2'l is clamped between thecover and casing by suitable bolts 28 which hold the cover in place. Thecover 25 is preferably made ,of cast steel or a die forging so as to 1center of this surface to its outer periphery and is connected to thesource of lubricant supply by.

narrow. inclined attenuating groove 35 in the plug surface which isconnected at one end with a longitudinal groove 22 and communicates atits other end with the shoulder 32.

. The cover 25 has a threaded opening 31 atitsj center into which athreaded lubricant screw 38 is ritted, and lubricant may be introducedthrough this opening into the pressure chamber 39 formed between thecover and diaphragm. Upon turning the screw 38 inwardly pressure isexerted on the lubricant in the chamber 38, and this pressure istransmitted unirormly across the large end of the plug by the diaphragm2"! to hold the plug in its seat. If desired, an opening 41! may beprovided communicating at one end with port 5 and extending through theplug to balance line pressure on the plug.

In operation line pressure exerts a force on the plug tending to liftthe plug out of its seat, and this force is balanced by applyingsufiicient pressure to the lubricant in chamber 39 by means of thelubricant screw 38 to maintain the plug seated. The unyielding hydraulicpressure of the lubricant in chamber 39 bears uniformly against theinner surface of resilient cover 25 which may yield by its inherentresilience and thus yieldingly holds the plug in its seat. The plug islubricated and jacked by the application of pressure to the lubricant inchamber II by means of screw l3, and it will be apparent that jacking ofthe plug from its seat is allowed by the resilient cover 25 which yieldsas pressure is applied to lift the plug from its seat. Friction betweenthe diaphragm 27 and the large end of the plug is reduced by lubricantsupplied thereto at a lag in pressure by the spiral groove 34 by meansof shoulder 32, and attenuating groove 35 connected to longitudinalgroove 22 which in turn is connected to lubricant chamber In the closedposition of the valve there is substantially a complete seal around eachport formed by lubricant chamber II, a longitudinal groove 22,- oneextension groove l9, circumferential groove H, the other extensiongroove l9, and a longitudinal groove 23. In rotating the valve to openposition the longitudinal grooves 23 are exposed to line fluid, but arecut oil from the source of lubricant pressure because they aredisconnected from their respective extension grooves Hi and 2D. In openposition a similar complete seal around the port is provided by thechamber I a longitudinal groove 22, one extension groove 20,circumferential groove I8, the other extension groove 2|], and alongitudinal groove 23.

In the modification shown in Figure 3 the casing 4| has the usualpassageway 42 thereto for flow of fluid and a tapered seat 43 formedtransversely thereof. The plug 44 has a port 45 therethrough for flow offluid, and an operating stem 46 is provided at the larger end of theplug, preferably integral therewith. A threaded lubricant reservoir 41is provided in the valve stem and connects with a duct 48 cored throughthe valve and extending to the bottom chamber 49. As the lubricatingsystem in thismodiflcation beginning with chamber 49, which correspondsto chamber l, is exactly like that shown in Figure 1, the descriptionthereof need not be repeated. A shoulder 5| is provided at the large endof the plug where it joins the stem, the edge of the shoulder beingrabbeted at 52.

A shoulder 53 is provided adjacent the large end of the seat, and ametal diaphragm or washer 54 is located on the shoulder 53 and rests onthe shoulder 5| of the plug. A metal spacer 55 is located on thediaphragm 54, and a second diaphragm 56 rests on the spacer, and on ametal thrust ring 51 resting on the diaphragm 54 adjacent the valvestem. The diaphragms 54 and 55 are retained in place by a resilientcover 58 which bears thereon and is secured in place by bolts 59, thecenter of the cover being bored at 6| to receive the valve stem 46. ,Ametal ring 62 is located in the bore 6| on the top diaphragm 56 and apacking ring 63 of resilient material is superposed on metal ring 62,both rings 52 and 63 being pressed against diaphragm 56 by a gland 64bolted or otherwise secured to the cover. Thus, it will be seen that theinner edge of diaphragm 54 is held in fluid tight relation between theshoulder 5| of the plug and thrust ring 51, and diaphragm 56 is held influid tight relation at its inner edge between thrust rings 51 and 62.The outer edges of diaphragms 54 and 56 are held fluid tight by thecover 58 and spacer ring 55, gasket 55 being used, if desired, to ensurea fluid tight joint. Friction between theshoulder 5| of the plug and thediaphragm 54 is reduced by lubricant supplied thereto by a spiral groove60 in the plug shoulder which extends inwardly from the rabbet 52 to theplug stem. The plug therefore is resiliently urged into its seat by thepressure of the resilient packing ring 63 transmitted thereto by thrustrings 52 and 51. However, it is preferred to utilize the resilientreaction of cover 58 as the main plug seating force.

A bore 66 which is L-shaped in vertical section is formed in filler ring55, the horizontal portion of which communicates with the chamber 61formed between the diaphragms 54 and 56, and the vertical portion ofwhich registers with a threaded bore 68 in the cover 58, the hole beingextended through gasket 65. A lubricant screw 69 closely fits thethreaded bore 68.

In operation, the gland 64 is adjusted to exert sufficient pressure tomaintain a fluid tight joint between the plug shoulder 5|, thrust ring51 and 62 and the diaphragms 54 and 56 clamped therebetween, thereaction of the resilient cover 58 urging the plug into its seat. Whenit is desired to increase the seating pressure on the plug, a quantityof heavy lubricant is introduced in threaded bore 58 and is forced byscrew 69 into the chamberil, where the hydraulic force of the lubricantis evenly distributed over the plug shoulder and resilient cover, andforces the valve into its seat. The resiliency of the cover allows theplug to be jacked by lubricant under pressure in chamber The inventionmay be embodied in other speciflc forms without departure from thespirit or essential characteristics of the present invention. Thespecific form described herein therefore is to be considered in allrespects as illustrative and not restrictive of the invention.

What is claimed and desired to be secured by United States LettersPatent is:-

1. In a plug valve, a casing having a passageway therethrough for flowof fluid and a bore formed transversely of the passageway, a rotatableplug located in said bore, an inherently resilient cover closing one endof the bore, flexible means interposed between the cover and valvecasing and providing a fluid chamber with the cover, and means forapplying fluid under pressure to said chamber to deflect the cover andyieldingly urge the plug in a longitudinal direction.

2. In a plug valve, a casing having a passage way therethrough for flowof fluid and a bore formed transversely of the passageway, a rotatableplug seated in said bore, a diaphragm closing one end of the bore, aninherently resilient cover clamping the diaphragm against the moan: 7

body and providing a chamber between the diaphragm and cover, means forintroducing fluid into said chamber, and means for applying pres-e sureto thelfluid thereinfor urging the plug into its seat V 3. In aplugvalve, a casing having a passageway 'therethrough for flow of fluidand a tapered seat formed transversely of the passageway, a tapered plugseated in said seat, a flexible diaphragm closing the larger end of theseat, a resilient cover clamping the diaphragm against the body andproviding a fluid chamber between the cover and diaphragm, means forintroducing fluid under pressure into said chamber for deflecting thecover and resiliently urging the plug into its seat, and means forjacking the plug from its seat by lubricant pressure.

4. In a plug valve, a casing having a passageway thcrethrough for flowof fluid and a bore formed transversely of the passageway, a plug havinga flat end surface in said bore, a diaphragm bearing on the casing andsurface, a second diaphragm spaced from the first diaphragm, aninherently resilient cover for clamping said diaphragms to the casing attheir outer peripheries,

means to clamp said diaphragms against said ph'ragm and cover andbearing on the larger end of the plug, means for applying fluid underpressure to said chamber to deflect the cover and yieldingly urge theplug into its seat, and means for lubricating the bearing surface of theplug and diaphragm.

6. In a plug valve, a'casing having a passageway therethrough for'flowof fluid and a tapered seat formed transversely of the passageway, ,atapered plug seated in said seat andhaving a reduced portion providingan operating stemand shoulder, a diaphrgamjassembly comprising aplurality of diaphragms held in spaced relation to provide a chambertherebetween resting on said casing and shoulder, an inherentlyresilient coverclamping said diaphragm assembly to the casing at itsouter periphery, means to clamp the inner portion of said diaphragmassembly against reduced portionproviding an operating stem and coverand yieldingly urge the plug into its seat,

and means to introduce lubricant under pressure the plug into its seat.i 11. In a plug valve, a valve comprising a casbetween saiddiaphragmassembiy and shoulder oi. the plug. I x V 8. In aplug valve, acasing having a passageway therethrough for flow of fluid and a taperedfor jacking the plug by lubricant under pressure, and means to introducelubricant under pressure between said diaphragm and bearing surface ofthe'plug.

9. In a plug valve, a valve casing, a rotatable valve plug disposedwithin the casing, said plug being reduced at one end to provideanoperating stem and an annular shoulder adjacent said stem, an expansiblechamber assembly of substantially annular shape resting on the plugshoulder and casing, an inherently resilient cover clamping saidassembly to the casing, a substantially spiral lubricant channelextending from the edge of said shoulder to the stem, means forsupplying viscous lubricant under pressure to said channel, and means tosupply lubricant under pressure to said chamber as- 5 sembly.

10. In a plug valve, a valve comprising a casing having a passagewaytherethrough and a tapered valve seat therein, a plug seated in thevalve seat and having a hole adapted to register with the passageway,the casing being provided with an annular recess surrounding the upperend of the tapered valve seat, an expansible chamber assembly comprisingtwo spaced metal diaphragms forming a chamber therebetween seated in therecess and extending to the valve stem, an inherently resilient valvecover for fix edly holding the outer rim of the assembly against thecasing, means for adjustably holding the inner portion of the assemblyagainst the top of the larger end of the plug, and means for introducinglubricant under pressure to said chamber to deflect the cover andresiliently urge ing having a passageway therethrough and a taperedvalve seat therein, a plug seated in the valve seat and having a portadapted to register with the passageway, the larger end of the plugbeingreduced to provide anannular shoulder and operatingstem, the casingbeing provided with an annular recess surrounding the upper end of thetapered valve seat, an annular diaphragm seated in said recess andresting on the plug shoulder, an expansible chamber assembly comprisinga spacer ring resting on the dia phragm surrounding the valve stem, alarger spacer ring resting on the diaphragm in said recess, a secondannular diaphragm resting on said spacer rings to provide a chamberbetween said diaphragms, an inherently resilient valve cover fixedlyholding the outer edges of said chamber assembly against the casing, athrust ring surrounding the stem and resting on the second diaphragm, agland for adjusting the pressure of said thrust ring against theassembly, and means for introducing lubricant under pressure to saidchamber to deflectthe cover and resiliently urge the plug into its seat.

12. In a plug valve, a casing having a pas- 4 2,1oa,a11

sageway therethrough iornflow of fluid and a bore formed transversely ofthe passageway, a rotatable plug located in said bore, one end of saidplug having a substantially flat portion, a cover for said bore meansabutting the flat portion of said plug and, providing an expansiblechamber with said cover capable of expansion under internal pressure,and means of. lesser area than the area of contact between said firstmeans and the fiat portion 0! the plug for compressinn fluid underpressure in said chamber to urge the plug into its seat.

SVEN J. NORDSTROM.

